Amino-halogen-thiophanthraquinones



Patented July 10, 1951 AMINO-HALOGEN-THIOPHANTHRA- QUINONES Herman E.Schroeder, Kennett Square, Pa., and

Lorraine A. Ringrose, Wilmington, Del., assignors to E. I. du Pont deNemours & Company, Wilmington, Del., a corporation of Delaware NoDrawing. Substituted for abandoned application Serial No. 99,879, June17, 1949. This application January 19, 1951, Serial No. 206,930

6 Claims. 1

This invention relates to new thiophanthraquinone compounds, and moreparticularly to new halogenated aminothiophanthraquinones which may berepresented by the general formula:

S 7 2 NHr-p )n 5 lg in which the amino group is attached to the benzenenucleus of the thiophanthraquinone in one of the positions 5, 6, '7 and8, X stands for chlorine or bromine which is attached in the benzenenucleus and at least one of which is in a position ortho or para to theamine group, and n stands for one of the numerals 1 and 2.

This application is filed as a substitute for our application Serial No.99,879 filed June 17, 1949, now abandoned.

It is an object of this invention to preparehalogen-aminothiophanthraquinones of the above general formula which arevaluable intermediates in the preparation of dyes and which also serveas dyes in themselves, particularly for cellulose acetate fibers, nylon,etc. 7 While a consideration of the reactivity of thiophene would leadone to expect that in the halogenation of aminothiophanthraquinone thehalogen would react on the thiophene nucleus before any successfulsubstitution in the benzene ring could be effected, we have found thathalogen-aminothiophanthraquinones having desirable properties as dyeintermediates, particularly for dyes of the anthraquinone vat dyeseries, may be prepared by the reaction of aminothiophanthraquinones inwhich the amino group is in one of the positions 5, 6, 7 and 8 withchlorine or bromine and by the elimination of halogen in the polyhalogenated aminothiophanthraquinones. In these processes products areobtained in relatively pure form without any substitution of halogen inthe thiophene ring of the thiophanthraquinone molecule.

Where the halogen-aminothiophanthraquinones are to be used asintermediates in the 2. bromine or chlorine is preferably carried out inan inert organic solvent such as nitrobenzene or in an aqueous mediumsuch as water or in a dilute acid solution. The halogenation is usuallycarried out at temperatures of from to 160 0., although it will beobvious that this temperature can be varied, depending on the particularsolvent and other conditions employed. Halogenation catalysts such asiodine may be used.

The following examples are given to illustrate the invention. The partsused are by weight.

Example 1 A mixture of 320 parts of water, 32 parts of 36% hydrochloricacid, 10 parts of 8-.-aminothiophan thraquinone is heated to the boil,then cooled to 15-20 C., and a solution of 16 parts of bromine in 42parts of glacial acetic acid is added over a period of one hour. Thecharge is stirred at room temperature for several hours, then heated at80-90 C. for four to five hours, cooled to room temperature andfiltered. The violet-red crystals line product is washed acid-free,slurried in dilute ammonia, filtered off, washed alkali-free with waterand dried. This product has a melting range of 235238 0., and analyzes40.2% bromine and 3.58% nitrogen. The8-amino-5,7-dibromothiophanthraquinone is represented by the formula:

Example 2 phanthraquinone. I The charge is heated at C. for three hours,then cooled and drowned in 800 cc. of cold water; The productisfiltered, washed acid-free with water, slurried in' dilute ammonia,filtered, washed alkali-free and dried. Recrystallization frommonochlorobenzene gives a brown-orange crystalline product which has amelting range of -188 C. and analyzes 26.4%

bromine, 4.37% nitrogen and 10.9% sulfur.

represented by the formula:

NH, (I?

Example 3 A solution of 21 parts of bromine in 21 parts of acetic acidis added dropwise at room temperature to a mixture of 100 parts ofnitrobenzene and parts of '7-aminothiophanthraquinone. The charge isstirred several hours at room temperature, heated at 80-85 C. for two tothree hours, then heated at 140150 C. for 3%; hours, cooled andfiltered. The cake is washed with benzene, slurried in water and thebenzene is removed by heating the slurry to boiling. The orange-redneedle-like product is filtered, washed and dried. It has a meltingrange of 2'75280 C. and analyzes 41.3% bromine and 3.67% nitrogen. The6,8-dibromo-Y-aminothiophanthraquinone is represented by the formula:

Br 0 I ll It is Example 4 Example 5 The 7 amino6-bromothiophanthraquinone may be prepared by the addition of 7.7 partsof bromine in 15 parts of acetic acid to 10 parts of'7aminothiophanthraquinone in 100 parts of nitrobenzene, as described inExample 3. The product is recrystallized from ortho-dichlorobenzene inthe form of yellow-orange needles, and has a melting range of 305-,30'lC. It analyzes 26.29% bromine, 4.4% nitrogen and 10.04%; sulfur.

Example 6 A solution of 7.2 parts of bromine in 5.8 parts of sulfurylchloride is added over a period of to minutes to a mixture of 160 partsof nitrobenzene, 0.05 part of iodine and 20 parts of 8-benzoylaminothiophanthraquinone (prepared by benzoylation of 8-aminothiophanthraquinone by usual methods). The charge is heated to103i4 C. and held there for 3 hours, then cooled to 8 C., stirred forone hour and filtered. The yellow-orange crystalline product isdebenzoylated as follows:

To 100 parts of 82% sulfuric acid is added at C. ten (10) parts of8-b-enzoylamino-5-bromothiophanthraquinone (prepared as describedabove). The charge is held at 8085 C. for one hour, cooled and drownedin 300 cc. of ice Water. The orange-colored product is filtered off,washed with water, slurried in dilute ammonia, filtered, washedalkali-free with water and dried. It has a melting range of 232235 C.and analyzes 25.23% bromine and 4.56% nitrogen. The 8- amino 5bromothiophanthraquinone is represented by the formula:

i ll Br 0 The8-amino-5-chlorothiophanthraquinonemay also be prepared bychlorination of 8-.benzoylaminothiophanthraquinone with sulfurylchloride, followed by debenzoylation of the B-benzoylamino 5chlorothiophanthraquinone, as described in this example.

Example 7 A solution of 5 parts of sulfuryl chloride in 10 parts ofnitrobenzene is added slowly over several hours to a mixture of 60 partsof nitrobenzene and '7 parts of 7-aminothiophanthraquinone below 20 C.The charge is stirred one hour at 20 C., then several hours at 30 C.,and filtered at l520 C. The cake is washed with nitrobenzene andalcohol, then slurried in dilute soda ash solution and the yellow-orangeneedle-like product is filtered, washed alkali-free with water anddried. It has a melting range of 231- 233 0., and analyzes 13.88%chlorine and 12.07%

sulfur. The 8 chloro 'I-aminothiophanthraquinone is represented by theformula:

c1 (3 NH /S J As illustrated above, the new products of this inventionmay be prepared by halogenating the acylated aminothiophanthraquinoneswith subsequent deaoylation to give the free amino compound. They mayalso be prepared by halogenating the aminothiophanthraquinone to apolyhalogenated compound and then dehalogenating by the usual methods.such as with aniline in the presence of concentrated sulfuric acid.

In the same manner as illustrated in the above examples whereillustrations have been given for the general procedure for thepreparation of this new class of compounds, otheraminohalogenthiophanthraquinones can be produced, for instance, the6-aminothiophanthraquinone when b-rozninated. in the same manner asgiven in Example 3 gives the 6-a1nino-5,'l-dibromothiophanthraquinonewhich is an orange product somewhat redder in shade than the7-amino-6,8-dibromothiophanthraquinone. The 6-amino-7bromothiophanthraquinone may be obtained from the6amino-5,'7-dibrornothiophanthra quinone by the same procedure asdescribed in Example 4 for the isomeric product. The 5-aminothiophanthraquinone may be brominated by the same process asdescribed in Example 1 to give the 5 amino 6,8dibromothiophanthraquinone, and this compound may be partiallydebrominated, as more particularly described in Example 2, to yield the5-amino-6-bromothiophanthraquinone.

The halogenated aminothiophanthraquinones are excellent colors forsynthetic fibers such as cellulose acetate or nylon, giving brightdyeings deeper in hue and showing generally better light-fastness whencompared with the corresponding anthraquinone derivatives. The shade ofsome of these new compounds on cellulose acetate is as follows:

8 chloro-7-aminothiophanthraquinoneGolden 8 -am'ino-7-bromothiophanthraquinone-Red 8amino-5-bromothiophanthraquinorie-Scarlet 8 amino 5,7dibromothiophanthraquinone- Pink These compounds exhibited similarbehavior in the dyeing of nylon as they exhibited in the dyeing ofcellulose acetate fibers.

These new halogenated aminothiophanthraquinones are of particular valueas intermediates in the synthesis of new vat dyes, as well as in thesynthesis of dyes for W001 and synthetic fibers. The vat dyes producedfrom these new halogenaminothiophanthraquinone compounds in general aredeeper in shade and more readily vattable than the analogousanthraquinone dyes, and in general exhibit superior printing properties.From these new intermediates, colors of desirable shade and applicationand fastness properties are obtainable which have not heretofore beenavailable. The halogen-aminothiophanthraquinones of this invention areof special utility in the synthesis of valuable oxazole compounds moreparticularly described in copending applications Serial Nos. 99,877 and99,878.

The aminothiophanthraquinones employed as p the startin materials forthe production of the compounds of this invention may be prepared by theprocesses described in detail in U. S. Patent No. 2,501,132 of March 21,1950. The 8-aminothiophanthraquinone (having a melting point of 231-232C.) is preferably prepared from either the 3- orG-amino-ortho-(Z-thenoyl) -benzoic acids (or mixtures of the same) byefiecting ring closure in 10 parts of 96% to 100% sulfuric acid attemperatures of from 125 to 140 C. The 6- aniinothiophanthraquinone(having a melting point of 274-275 C.) is prepared in a similar mannerfrom either the 4- or 5-amino-ortho-(2- thenoyl) -benzoic acids, ormixtures of the same.

The 7-aminothiophanthraquinone (having a melting point of 271 C.) ispreferably prepared bythe ring closure of either the 4- or5-nitroorth-(2-thenoyl) -benzoic acids (or mixtures of the same) withsubstantially 100% sulfuric acid at temperatures of from 70 to 160 0.,with subsequent reduction of the nitro group. The ring closure may, ifdesired, be carried out in from one to ten minutes by maintaining thetempera ture at 120 to 160 where from 97% to 100% sulfuric acid isemployed. The nitro group may be reduced to the amine with sodiumhydrosulfite in sodium hydroxide solution. The -aminothiophanthraquinone(having a melting point of 235236 C.) may be prepared in the same mannerfrom the B-nitroor the 6-nitro-ortho-(2- thenoyl) -benzoic acids, ormixtures of the same.

The nitro-substituted ,thiophanthraquinones are more particularlydisclosed and claimed in U. S. Patent 2,501,131 of March 21, 1950.

The nitro-ortho-(2-then0yl) -benzoic acids used in the preparation ofthe above aminothiophanthraquinones may be prepared in good yields andpurity by the processes described in general in Lee & Weinmayr U. S.Patent 2,513,573 of July 4, 1950. The nitro-substituted phthalicanhydride may be reacted with the Grignard reagent prepared from2-bromo-thiophene or 2-iodothiophene, or it may be prepared bycondensing the nitrophthalic anhydride with thiophene by the usualFriedel-Crafts synthesis with the aid of aluminum chloride or similarcondensing agent. The 5-nitro-2-(2-thenoyl)-benzoic acid is'readilyobtained in good yields by reacting thiophene with2-carbomethoxy-5-nitrobenzoyl chloride in nitrobenzene in the presenceof aluminum chloride, followed by hydrolysis of the ester to thenitrothenoyl benzoic acid. The 2-carbomethoxy- .3-(and 5) -nitrobenzoicacids are preferably produced from the corresponding nitrophthalicanhydrides by carrying out the esterification in an inert organicdiluent which has a boiling point above C. but which exhibits negligiblesolvent action on the monomethyl ester, such as nitrobenzene or thechlorobenzenes, at 20 to 40 0., using from 1 to 1.1 mol proportions ofmethanol. The preparation of various nitrothenoyl benzoic acid methylesters is the subject of U. S. Patent 2,519,040 of August 15, 1950.Where the amino-ortho-(Z-thenoyl) -benzoic acid is desired, thecorresponding nitro compound may be reduced to the amine either incaustic solutions with zinc or iron or by means of hydrogen in thepresence of a nickel catalyst.

We claim:

l. The amino halogen thiophanthraquinone compounds of the followinggeneral formula.

( )n 5 II in which the amino group is attached to the henzene nucleus ofthe thiophanthraquinone in one of the positions 5, 6, 7 and 8, X standsfor halogen of the group consisting of chlorine and bromine whichhalogen is attached to the benzene nucleus,'at least one halogen beingin one of the positions ortho and para to the amine group, and 11.stands for one of the numerals 1 and-2.

2. The ortho amino chloro-thiophanthraquinones in which both the aminoand chlorine are contained in the benz ring of the thiophanthraquinonemolecule, which have the formula:

2,559,677 7 4. '7 'amino-6,8-dibromothiophanthraqulnone contained in thehem ring of the thlophanthraof the formula: quinone molecule, which havethe formula:

.5. -8-amino 5,7 dibromothlophanlphraqulnone HERMAN E. SCI-IROEDER. ofthe formula: LORRAINE A. RINGROSE. REFERENCES CITED BF w The followingreferences are of record in the 15 file of this patent:

-- UNITED STATES PATENTS l g Number Name Date 1,818,311 Drescher Aug.11, 1931 6. The ortho ammo-brom0-th10ph n r q 20 1,853,334 Lovemck May 719 2 nones in which both the amino and bromine are 2,084970 DettwflerJune 22 1937

1. THE AMINO - HALOGEN - THIOPHANTHRAQUINONE COMPOUNDS OF THE FOLLOWINGGENERAL FORMULA: IN WHICH THE AMINO GROUP IS ATTACHED TO THE BENZENENUCLEUS OF THE THIOPHANTHRAQUINONE IN ONE OF THE POSITIONS 5, 6, 7 AND8, X STANDS FOR HALOGEN OF THE GROUP CONSISTING OF CHLORINE AND BROMINEWHICH HALOGEN IS ATTACHED TO THE BENZENE NUCLEUS, AT LEAST ONE HALOGENBEING IN ONE OF THE POSITIONS ORTHO AND PARA TO THE AMINE GROUP. AND NSTANDS FOR ONE OF THE NUMERALS 1 AND 2.